Renewable fuel sources may be obtained by converting a biomass feedstock into useful biofuels and/or specialty chemicals. For instance, a bio-oil containing stream may be produced by subjecting a biomass feedstock to fast pyrolysis, slow pyrolysis, liquefaction, gasification, enzymatic conversion or another chemical conversion reaction in the presence of a catalyst, such as zeolite, in a biomass conversion unit.
Chemically combined minerals as well as metals (calcium, potassium, magnesium, sodium, manganese, aluminum, silicon, chromium, iron, phosphorus, sulfur, etc.) from the biomass accumulate on the catalyst during the conversion reaction. This dramatically decreases the surface area and the micropore volume of the catalyst and markedly influences physical chemical properties and performance of the catalyst. Catalytic activity is therefore significantly decreased.
Among the metals which accumulate on the catalyst, potassium has been found to be distributed across and within the catalyst particles, in contrast to calcium and magnesium which are enriched in the external shell of the particles. Potassium can poison the acidic sites of a zeolite catalyst, leading to a significant decrease in catalytic activity. Typically, regeneration of such catalytic materials requires the removal of the metal contaminants by harsh demetallization chemicals. In addition, this process is carried out ex-situ from the reaction system, and requires shutting down of the reactor, unloading the spent catalyst and then transporting the spent catalyst to a chemical processing facility.
An alternative process is needed for removing potassium from a metal contaminated catalyst used in a biomass conversion process by reactivating the catalyst. Such alternatives would desirably be conducted under milder conditions than those presently offered and render restoration of the physical chemical properties of the catalyst.
It should be understood that the above-described discussion is provided for illustrative purposes only and is not intended to limit the scope or subject matter of the appended claims or those of any related patent application or patent. Thus, none of the appended claims or claims of any related application or patent should be limited by the above discussion or construed to address, include or exclude each or any of the above-cited features or disadvantages merely because of the mention thereof herein.